The House of Canossa was an Italian noble family from Lucca holding the castle of Canossa, from the early tenth to the early twelfth century.
Sigifred of Lucca built the castle at Canossa around 940. Adalbert Atto appears in Canossa in time to give refuge to Queen Adelaide when she was fleeing Berengar II and Willa in 955.
Matilda of Tuscany (Italian: Matilde di Toscana; Latin: Matilda or Mathilda; c. 1046 – 24 July 1115), or Matilda of Canossa (Italian: Matilde di Canossa [maˈtilde di kaˈnɔssa]), also referred to as la Gran Contessa ("the Great Countess"), was a member of the House of Canossa (also known as the Attonids) in the second half of the eleventh century. Matilda was one of the most important governing figures of the Italian Middle Ages. She reigned in a time of constant battles, political intrigues, and excommunications by the Church.
She ruled as a feudal margravine and, as a relative of the imperial Salian dynasty, she brokered a settlement in the so-called Investiture Controversy. In this extensive conflict with the emerging reform Papacy over the relationship between spiritual (sacerdotium) and secular (regnum) power, Pope Gregory VII dismissed and excommunicated the Holy Roman Emperor Henry IV (then King of the Romans) in 1076. At the same time, Matilda came into possession of a substantial territory that included present-day Lombardy, Emilia, Romagna, and Tuscany. She made the Canossa Castle, in the Apennines south west of Reggio Emilia, the centre of her domains.
Sigifred of Lucca (also Sigefred, Siegfried) (died after 940) was a Lombard nobleman and the progenitor of the House of Canossa.
Donizo, the 12th-century biographer of the Canossa dynasty, refers to Sigifred as coming from ‘the county of Lucca’ (de comitatu Lucensis). Little is known about Sigifred. Although he was from Lucca, he was probably not count of Lucca. He moved from Tuscany to Emilia-Romagna c.924-930 when Hugh of Italy endowed him with lands around Parma. Sigifred also gained control of lands around Brescia.